SUUNTO VYTEC DS - Manual (Page 69)

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Also on repetitive dives adjustment may be applied to the maximum al-
lowable nitrogen overpressure in each theoretical tissue group.
Depending on circumstances Suunto RGBM will adapt the decompres-
sion obligations by doing any or all of the following:
• Reducing no-decompression stop dive times
• Adding Mandatory Safety Stops
• Increasing decompression stop times
• Advising an extended surface interval (Diver Attention symbol).
Diver Attention Symbol – Advice to Extend Surface Interval. If attenuated
RGBM (RGB50) has been set, the Diver Attention Symbol will also be
shown to indicate it.
Some patterns of diving cumulatively add a higher risk of DCI, e.g. dives
with short surface intervals, repetitive dives deeper than earlier ones,
multiple ascents, substantial multiday diving. When this is detected in ad-
dition to adapting the decompression algorithm the Suunto RGBM model
will in some circumstances also advise, with the Diver Attention Symbol
(review chapter 3.6) that the diver extend the surface interval.
6.3. OXYGEN EXPOSURE
The oxygen exposure calculations are based on currently accepted expo-
sure time limit tables and principles. In addition to this the dive computer
uses several methods to conservatively estimate the oxygen exposure.
These include for example:
• the displayed oxygen exposure calculations are upped to the
next higher percentage value
• for recreational scuba diving, the recommended upper limit of
1.4 bar PO
2
is used as a default
• the CNS% limits up to 1.6 bar are based on 1991 NOAA Diving
Manual limits
• the OTU monitoring is based on the long-term daily tolerance
level and the recovery rate is reduced
Oxygen related information displayed by the dive computer is also de-
signed to ensure all warnings and displays in the appropriate phases of
a dive. E.g. the following information will be shown before and during a
dive, when the computer is set in Nitrox mode:
• the selected O
2
%
• the color-coded OLF% bar graph for either CNS% or OTU%
• audible alarms are given and the OLF bar graph starts to blink
when the 80% and 100% limits are exceeded